March 31, 2020
Below is a link to a stacked video comparison of breaststroke swam well, and not so well. The focus in this very short video clip should be on the principle of letting the head move with your torso through the stroke.
The top video shows a lot of head movement from the neck, independent of the torso. This leads to instability and a fair amount of momentum conflict between the weight of the head and the rest of the body. You can probably see the interruption in forward progress from the head being thrown up to the breath, then being thrown down back into the water.
The bottom video shows the swimmer letting the head remain connected to their torso, allowing the mass of the torso and head to move together through the full stroke. You should be abe to see a comparable improvement in overall forward progress compared to the top video.